ananyo writes: "When influenza hit early and hard in the United States this year, it quietly claimed an unacknowledged victim: one of the cutting-edge techniques being used to monitor the outbreak. A comparison with traditional surveillance data showed that Google Flu Trends, which estimates prevalence from flu-related Internet searches, had drastically overestimated peak flu levels. The glitch is no more than a temporary setback for a promising strategy, experts say, and Google is sure to refine its algorithms. But with flu-tracking techniques based on mining of web data and on social media taking off, Nature looks at how these potentially cheaper, faster methods measure up against traditional epidemiological surveillance networks."